Clip fasteners are used in various industries, e.g., the automobile industry, e.g., to attach and assemble moldings, trim pieces and other components to panels and other such members; the electronic and communications industry, e.g., to assemble and attach electronic chassis assemblies to support structures, such as equipment racks and cabinets.
The fasteners are formed with retaining tabs which are sheared and formed from side legs, so when the fastener legs are inserted in a component opening, the tabs resiliently engage the edges of the opening to retain the fastener in place. An adjustable snap fit member extending through a second component is turned down through an aperture in the fastener to mechanically join the two components.
Alternatively the fasteners can attach to the component by means of a glued, or otherwise permanently adhered, connection, which would permit the fastener to be permanently attached to the upper component in an adjustable assembly.
The clip fasteners of this general type have been intended for securement to relatively rigid components or members made of metal or plastic. In order to prevent the fastener from turning relative to the component when torque is applied to the adjustable snap fit member used to join the two components, the component opening receiving the fastener is made rectangular or given some other irregular shape or the fastener and component are provided with abutting shoulders.
An example of a fastener abutting the component, includes wherein a U-nut clips into an opening in the component spaced at a specific distance from the edge. The edge of the component abuts the U-nut hinge surface and prevents the U-nut from turning. Another example is a fastener of the general type requiring a rectangular opening on the component to prevent the fastener from turning relative to the component when torque is applied to the adjustable snap fit member used to join the two components.
The fastener can engage into the threaded component by means of a diamond-shaped, star-shaped, or other shaped connection which has the function of incorporating corners, points or abutting shoulders to engage the pieces together to transmit rotational forces applied during turning of the screw head.
Fasteners of the general type requiring to be installed in a rectangular opening on the component are limited in their scope of application and use. The rectangular opening is usually of a unique shape that requires the use of a special sheet metal punch and die-set to form it. In a high volume production environment it is very undesirable to use rectangular shaped metal punches because the sharp corners wear out quickly and therefore the opening produced fails to meet its dimensional specifications. The parts produced are rejected and production is suspended while the die-sets are replaced. Another unfavorable factor is the high levels of stress concentration at the sharp corners of the opening, which under a vibration environment cause the sheet metal to fatigue and crack open, causing the strength of the joint to weaken and the fastener to lose its grip on the component. The same mode of failure occurs on a rectangular opening in a plastic panel. On an automobile, exposed to weather and the elements, the cracked sheet metal corrodes and the integrity of the entire automobile is deteriorated.
Known fasteners suffer from one or more of a number of disadvantages, especially the ability to provide attachment of different components and to be axially adjustable to align different surfaces of different components, as well as others, e.g.: a) A single formed adjustable snap fit member thread on the head of many fasteners limits the amount of torque the fastener can withstand and the amount of holding force it can applied to the component. The capacity of the holding adjustable snap fit member is also limited by the single formed adjustable snap fit member thread on the head of the fastener; b) The need of a rectangular opening or an irregular shape opening to prevent the fastener from turning is a structural integrity issue and a product reliability issue. The need of a special punch and die-set for fabrication of the component is a manufacturing issue and concern; c) U-nut types of fastener is limited by its need to be installed abutting the edge of a panel (e.g., it cannot easily be installed inside an existing panel); and/or d) Clip fasteners are restricted in their use by only large manufacturing facilities who have access to the machine tools and the punches used to form the special shape openings required for their installation. The general public cannot use these fasteners simply because the tools required for their installation are not readily available and easy to use.
Thus, a need exists for one or more of a low cost, blind snap mounted clip fastener for anchoring into a round or square hole, that is axially adjustable to align different surfaces, that is simple to manufacture, that, easy to use, that is provided with a simple feature that prevents it from rotating relative to the component and in combination with other features, such as prevailing torque, self-locking and multiple engaging threads. The need exist for a fastener of this general type be available to the general public and for a variety of commercial and residential applications.